Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753100Ab2E3Lfq (ORCPT ); Wed, 30 May 2012 07:35:46 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:62086 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752978Ab2E3Lfp convert rfc822-to-8bit (ORCPT ); Wed, 30 May 2012 07:35:45 -0400 MIME-Version: 1.0 In-Reply-To: <1338371317-5980-6-git-send-email-glommer@parallels.com> References: <1338371317-5980-1-git-send-email-glommer@parallels.com> <1338371317-5980-6-git-send-email-glommer@parallels.com> From: Paul Turner Date: Wed, 30 May 2012 04:35:13 -0700 Message-ID: Subject: Re: [PATCH v3 5/6] Also record sleep start for a task group To: Glauber Costa Cc: linux-kernel@vger.kernel.org, cgroups@vger.kernel.org, devel@openvz.org, Peter Zijlstra , Tejun Heo , "Eric W. Biederman" , handai.szj@gmail.com, Andrew.Phillips@lmax.com, Serge Hallyn Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1794 Lines: 46 On Wed, May 30, 2012 at 2:48 AM, Glauber Costa wrote: > When we're dealing with a task group, instead of a task, also record > the start of its sleep time. Since the test agains TASK_UNINTERRUPTIBLE > does not really make sense and lack an obvious analogous, we always > record it as sleep_start, never block_start. > > Signed-off-by: Glauber Costa > CC: Peter Zijlstra > CC: Paul Turner > --- > ?kernel/sched/fair.c | ? ?3 ++- > ?1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index c26fe38..d932559 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -1182,7 +1182,8 @@ dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int flags) > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?se->statistics.sleep_start = rq_of(cfs_rq)->clock; > ? ? ? ? ? ? ? ? ? ? ? ?if (tsk->state & TASK_UNINTERRUPTIBLE) > ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?se->statistics.block_start = rq_of(cfs_rq)->clock; > - ? ? ? ? ? ? ? } > + ? ? ? ? ? ? ? } else > + ? ? ? ? ? ? ? ? ? ? ? se->statistics.sleep_start = rq_of(cfs_rq)->clock; You can't sanely account sleep on a group entity. Suppose you have 2 sleepers on 1 cpu: you account 1s/s of idle Suppose you have 2 sleepers now on 2 cpus: you account 2s/s of idle Furthermore, in the latter case when one wakes up you still continue to accrue sleep time whereas in the former you don't. Just don't report/collect this. > ?#endif > ? ? ? ?} > > -- > 1.7.10.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/